A friend of mine occasionally has this problem. While its troubling that there doesn't appear to be an actual solution, she works around it by running Guild Wars 2 with the -repair switch.

Right-click your Gw2.exe shortcut (or make a new one for this), go to Properties and in the Target: field, keep what's there but add -repair to the end. The whole thing should look something like

Target: "C:\Guild Wars 2\Gw2.exe" -repair

Run that shortcut and let the repair process complete, then try to retrieve your character. It may not prevent the problem from happening again later, but you should at least be able to get back to the world.